U.S. patent application number 09/925790 was filed with the patent office on 2002-03-07 for method and apparatus for manufacturing synthetic resin hollow member incorporating an intermediate element therein and the synthetic resin hollow member.
Invention is credited to Nishida, Shoso, Takemoto, Yoshihiro.
Application Number | 20020027099 09/925790 |
Document ID | / |
Family ID | 18038649 |
Filed Date | 2002-03-07 |
United States Patent
Application |
20020027099 |
Kind Code |
A1 |
Takemoto, Yoshihiro ; et
al. |
March 7, 2002 |
Method and apparatus for manufacturing synthetic resin hollow
member incorporating an intermediate element therein and the
synthetic resin hollow member
Abstract
Method and apparatus for manufacturing a synthetic resin-made
hollow member incorporating an intermediate element are provided
which enable operations of molding half bodies, abutting and
joining the half bodies together, and molding an intermediate
element in a series of steps, and which eliminate the necessity of
such a manual work as may otherwise be required in incorporating
the intermediate element into the half bodies. A pair of rotary
injection molding dies are used which can be opened and closed
relative to each other and are rotatable relative to each other
over an angle of 60.degree. for each turn, each die having a half
body molding section including one male molding portion and two
female molding portions in the direction of rotation for each
rotational run over an angle of 120.degree., each die also having
an intermediate element molding portion provided between specified
half body molding portions in the direction of each rotational run
over an angle of 120.degree.. In each two rotational runs of the
molding dies, a series of steps is carried out including first
injection for molding a pair of half bodies and an intermediate
element, molded product setting for matching two half bodies with
the intermediate element set in place and abutting the two half
bodies against each other, and second injection for injecting
melted resin onto the abutting portions and joining the two half
bodies, whereby a hollow member with the intermediate element set
between the two half bodies can be obtained.
Inventors: |
Takemoto, Yoshihiro;
(Higashihiroshima-shi, JP) ; Nishida, Shoso;
(Hiroshima-shi, JP) |
Correspondence
Address: |
Harold C. Wegner
FOLEY & LARDNER
Washington Harbour
3000 K Street, N.W., Suite 500
Washington
DC
20007-5109
US
|
Family ID: |
18038649 |
Appl. No.: |
09/925790 |
Filed: |
August 10, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09925790 |
Aug 10, 2001 |
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09189150 |
Nov 10, 1998 |
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6299816 |
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Current U.S.
Class: |
210/321.84 ;
264/250; 264/254; 264/263; 425/116; 425/120; 425/121; 425/129.1;
425/130 |
Current CPC
Class: |
B29C 2045/0067 20130101;
B29C 66/54 20130101; B29C 45/0062 20130101 |
Class at
Publication: |
210/321.84 ;
264/250; 264/254; 264/263; 425/116; 425/120; 425/121; 425/129.1;
425/130 |
International
Class: |
B01D 063/00; B29C
045/14; B29C 045/16 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 14, 1997 |
JP |
9-313227 |
Claims
What is claimed is: (For US)
1. A method of manufacturing a synthetic resin hollow member
incorporating an intermediate element wherein after the
intermediate element is disposed between a pair of synthetic
resin-made half bodies, the half bodies are brought into abutment
with each other and joined together at their abutting portions,
whereby the synthetic resin hollow member incorporating the
intermediate element is produced, the method comprising: using a
pair of rotary injection molding dies which can be opened and
closed relative to each other and are rotatable relative to each
other at angular intervals of (360/6 n) degrees, each die having a
half body molding section consisting of at least one male molding
portion and two female molding portions in a repetitive sequence of
male/female/female in the direction of rotation for each rotational
run over an angle of (360/3 n) degrees, each die also having an
intermediate element molding portion provided between specified
half body molding portions in the direction of rotation for each
rotational run over an angle of (360/3 n) degrees, and a first die
clamping step for closing and clamping the molding die pair; a
first injection step for injecting a melted resin mass into a
molding cavity defined by closing the pair of molding dies for
molding a first half body and a second half body through a
combination of male and female portions and for molding an
intermediate element to be set between the half bodies through a
combination of intermediate element molding portions; a first die
rotating step for opening the pair of dies after the first
injection step and causing the dies to rotate for an angle of
(360/6 n) degrees relative to each other so that the intermediate
element is mated to and fitted in the first half body; a second die
rotating step for opening the pair of dies again after the first
die rotating step and causing the dies to rotate for a further
angle of (360/6n) degrees relative to each other so that the first
half body in which the intermediate element is set is mated to and
brought into abutment with the second half body through a
combination of female molding portions; a second die clamping step
for closing and clamping the pair of dies again after the second
die rotating step; and a second injection step for injecting a
melted resin mass onto abutting portions of the half bodies for
joining the two half bodies; whereby upon every two rotational runs
of the molding dies, a hollow member having the intermediate
element set in place between the first and second half bodies can
be obtained.
2. An apparatus for manufacturing a synthetic resin hollow member
incorporating an intermediate element wherein after the
intermediate element is disposed between a pair of synthetic
resin-made half bodies, the half bodies are brought into abutment
with each other and joined together at their abutting portions,
whereby the synthetic resin hollow member incorporating the
intermediate element is produced, the apparatus comprising: a pair
of molding dies assembled together so as to be opened and closed
relative to each other; rotary mechanism for rotating at least one
of the molding dies over an angle of (360/6 n) degrees for each
turn relative to the other molding die; and injection machine for
injecting a melted resin mass into a molding cavity defined by the
pair of molding dies being closed; the molding dies each having a
half body molding section consisting of at least one male molding
portion and two female molding portions provided in a repetitive
sequence of male/female/female in the direction of rotation for
each rotational run over an angle of (360/3 n) degrees, and an
intermediate element molding portion provided between specified
half body molding portions in the direction of rotational movement
for each (360/3 n) degrees; and wherein: for every two rotational
runs of the molding dies, a first injection is carried out such
that first and second half bodies are molded by a combination of
male and female molding portions, and an intermediate element to be
set between the first and second half bodies is molded by a
combination of intermediate element molding portions, and after the
intermediate element is mated to and fitted in the first half body
molded at the first injection step, the first half body in which
the intermediate element is set is mated to and abutted with a
corresponding second half body so that the half bodies are
assembled into a molded product, and a second injection is carried
out such that melted resin is injected onto the abutting portions
of the two half bodies for joining the half bodies together,
whereby for every two rotational runs of the molding dies, a hollow
member with the intermediate element set between the first and
second half bodies can be obtained.
3. A synthetic resin hollow member adapted to incorporate an
intermediate element therein by placing the intermediate element
between a pair of synthetic resin-made half bodies, then causing
the two half bodies to abut against each other and joining them at
their abutting portions, wherein: the synthetic resin hollow member
is manufactured by using a pair of rotary injection molding dies
which can be opened and closed relative to each other and are
rotatable relative to each other over an angle of (360/6 n) degrees
for each turn, each die having a half body molding section
consisting of at least one male molding portion and two female
molding portions in a repetitive sequence of male/female/female in
the direction of rotation for each rotational run over an angle of
(360/3 n) degrees, each die also having an intermediate element
molding portion provided between specified half body molding
portions in the direction of rotation for each rotational run over
an angle of (360/3 n) degrees; and for every two rotational runs of
the molding dies, a first injection is carried out such that first
and second half bodies are molded by a combination of male and
female molding portions, and an intermediate element to be set
between the first and second half bodies is molded by a combination
of intermediate element molding portions; after the intermediate
element is mated to and fitted in the first half body molded at the
first injection step, the first half body in which the intermediate
element is set is mated to and abutted with a corresponding second
half body so that the half bodies are assembled into a molded
product, and a second injection is carried out such that melted
resin is injected onto the abutting portions of the two half bodies
whereby the half bodies are joined together so that in every two
rotational runs of the molding dies, a finished product with the
intermediate element set between the first and second half bodies
can be obtained.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a method and apparatus for
manufacturing a synthetic resin hollow member incorporating an
intermediate element therein, for example, a synthetic resin-made
strainer having a filter incorporated therein, and to such a
synthetic resin hollow member.
[0002] Conventionally, when manufacturing such a synthetic resin
hollow item incorporating an intermediate element therein, for
example, a synthetic resin-made strainer having a filter
incorporated therein, one generally known method which would be
commonly considered is such that with a pair of synthetic
resin-made half bodies previously molded which constitute a pair of
shells of the hollow member, a separately manufactured intermediate
element is disposed between the two half bodies, the two half
bodies being then brought into abutment against each other and
bonded together through application of adhesive to the abutment
surface or by thermally melting the abutted portions, whereby a
finished hollow member incorporating the intermediate element is
obtained.
[0003] In this connection, it is also known to join the half bodies
by filling a melted resin mass into an interior resin passage or
outer peripheral resin passage formed along peripheral edge of the
abutting portions. It is also known to carry out such melted resin
loading into the resin passage by utilizing a molding die in which
separate half bodies are molded, when the separate half bodies are
joined together in such a way as aforesaid.
[0004] By employing such a method, it is possible to more stably
ensure high strength of bond between the so joined half bodies and
good sealing performance of the butt-joined portion as compared to
the prior art practice in which such joining is carried out by
adhesion or thermal melting.
[0005] Further, in Japanese Patent Application Laid-Open No.
7-217755, for example, there is disclosed a method utilizing the
so-called "die slide injection (DSI) method" wherein a die assembly
including a pair of dies is used such that one of the dies has a
male molding portion and a female molding portion for molding one
separate half body and the other die has a female molding portion
and a male molding portion provided in opposed relation to the
molding portions of the one die, and wherein after separate half
bodies are simultaneously molded by using the die assembly (first
injection), die opening is carried out once for insertion of a
separately made intermediate element into one of the half bodies
and one of the dies is caused to slide relative to the other die so
that separate half bodies left in respective female molding
portions are brought into abutment with each other before die
clamping, with melted resin being injected onto peripheral edges of
the abutting portions (second injection) to join the two half
bodies together.
[0006] According to this DSI method, productivity can be
considerably enhanced over the conventional method in which molding
of separate half bodies and abutting/joining of the half bodies are
carried out at separate stages.
[0007] An arrangement which can further enhance production
efficiency in the manufacturing of synthetic resin hollow members
is disclosed in, for example, Japanese Patent Publication No.
7-4830 which teaches a rotary injection molding die construction.
It dose not intend to consider of manufacturing synthetic resin
hollow members incorporating an intermediate element therein, but,
the above mentioned die construction is basically a combination of
molding dies adapted to be opened and closed relative to each other
such that one of the molding dies is rotatable relative to the
other die over a predetermined angular range, each die having a
molding section consisting of at least one male molding portion and
two female molding portions in a repetitive sequence of
male/female/female in the direction of rotation for each rotational
run over the predetermined angular range. In this conjunction,
there is also disclosed a rotary injection molding method
(so-called die rotary injection (DRI) method) wherein by using such
a molding die assembly, molding separate half bodies and joining a
pair of abutted half bodies are carried out during each cycle of
rotational (e.g., forward-reverse) movement so that a finished
product can be obtained for each cycle of rotational movement.
[0008] While, as stated above, productivity can be increased by
utilizing the die slide injection (DSI) over the conventional
practice in which the molding of half bodies and the abutting and
joining the half bodies are carried out in entirely different
stages, it has been still necessary that the intermediate element
be manufactured separately from the half bodies and be manually
inserted in place at the time of die opening midway during molding
operation.
[0009] This involves a problem that a stage for manufacturing an
intermediate element structure must be provided separately from the
stage for abutting and joining the half bodies together, and also,
it means that the need for troublesome manual operation cannot be
eliminated.
[0010] Therefore, it is a primary object of the present invention
to provide a method and apparatus for manufacturing a synthetic
resin-made hollow member incorporating an intermediate element
which enable operations of molding half bodies, abutting and
joining the half bodies together, and molding an intermediate
element in a series of steps, and which eliminate the necessity of
such a manual work as may otherwise be required in incorporating
the intermediate element into the half bodies, and an synthetic
resin-made hollow member produced by employing the method and
apparatus.
SUMMARY OF THE INVENTION
[0011] In order to accomplish the above mentioned object, according
to a first aspect of the present invention, there is provided a
method of manufacturing a synthetic resin hollow member
incorporating an intermediate element wherein after the
intermediate element is disposed between a pair of synthetic
resin-made half bodies, the half bodies are brought into abutment
with each other and joined together at their abutting portions,
whereby the synthetic resin hollow member incorporating the
intermediate element is produced, the method comprising: using a
pair of rotary injection molding dies which can be opened and
closed relative to each other and are rotatable relative to each
other at angular intervals of (360/6 n) degrees, each die having a
half body molding section consisting of at least one male molding
portion and two female molding portions in a repetitive sequence of
male/female/female in the direction of rotation for each rotational
run over an angle of (360/3 n) degrees, each die also having an
intermediate element molding portion provided between specified
half body molding portions in the direction of rotation for each
rotational run over an angle of (360/3 n) degrees; and carrying out
the following steps:
[0012] That is, a first die clamping step for closing and clamping
the molding die pair; a first injection step for injecting a melted
resin mass into a molding cavity defined by closing the pair of
molding dies for molding a first half body and a second half body
through a combination of male and female portions and for molding
an intermediate element to be set between the half bodies through a
combination of intermediate element molding portions; a first die
rotating step for opening the pair of dies after the first
injection step and causing the dies to rotate for an angle of
(360/6 n) degrees relative to each other so that the intermediate
element is mated to and fitted in the first half body; a second die
rotating step for opening the pair of dies again after the first
die rotating step and causing the dies to rotate for a further
angle of (360/6 n) degrees relative to each other so that the first
half body in which the intermediate element is set is brought into
abutment with the second half body through a combination of female
die molding portions; a second die clamping step for closing and
clamping the pair of dies again after the second die rotating step;
and a second injection step to be carried out after the second
clamping step for injecting a melted resin mass onto abutting
portions of the half bodies for joining the two half bodies.
[0013] By carrying out these steps, in every two rotational runs of
the molding dies, a hollow member having the intermediate element
incorporated between the first and second half bodies can be
obtained.
[0014] In the first aspect of the present invention, the method of
manufacturing a synthetic resin hollow member incorporating an
intermediate element comprises: using a pair of mold dies for
rotary injection molding (so-called DRI method) which can be opened
and closed relative to each other and are rotatable relative to
each other at angular intervals of (360/6 n) degrees, each die
having a half body molding section consisting of at least one male
molding portion and two female molding portions in a repetitive
sequence of male/female/female in the direction of rotation for
each turn of (360/3 n) degrees, each die also having an
intermediate element molding portion provided between specified
half body molding portions in the direction of rotation for each
rotational run over an angle of (360/3 n) degrees, and carrying out
a first injection step for molding a first half body, a second half
body and an intermediate element to be set between the half bodies;
a first die rotating step for causing the dies to rotate for an
angle of (360/6 n) degrees relative to each other so that the
intermediate element is mated to and fitted in the first half body
after the first injection step; a second die rotating step for
causing the dies to rotate for a further angle of (360/6 n) degrees
relative to each other so that the first half body in which the
intermediate element is set is mated to and brought into abutment
with the second half body; and thereafter, a second injection step
for injecting a melted resin mass onto abutting portions of the
half bodies for joining the two half bodies, whereby in each two
rotational runs of the dies a hollow member having an intermediate
element set between the first and second half bodies can be
obtained. Therefore, by employing the DRI method it is possible to
carry out the molding and butt-joining of half bodies, and also the
molding of an intermediate element in a series of steps. Also it is
possible to eliminate such manual work as has been involved in
setting the intermediate element in place.
[0015] That is, as compared with the prior art wherein adhesive
bonding or heat melting is carried out for joining separate half
bodies, high bond strength of joined half bodies and good sealing
characteristics of the butt-joined surface can be more stably
secured; and by using the DRI method it is possible to achieve
higher production efficiency.
[0016] According to a second aspect of the present invention, there
is provided an apparatus for manufacturing a synthetic resin hollow
member incorporating an intermediate element such that after the
intermediate element is disposed between a pair of synthetic
resin-made half bodies, the half bodies are brought into abutment
with each other and joined together at their abutting portions,
whereby the synthetic resin hollow member incorporating the
intermediate element is produced, the apparatus comprising: a pair
of molding dies assembled together so as to be opened and closed
relative to each other, rotary mechanism for rotating at least one
of the molding dies at angular intervals of (360/6 n) degrees
relative to the other molding die, and injection machine for
injecting a melted resin mass into a molding cavity defined by the
pair of molding dies being closed.
[0017] The molding dies each have a half body molding section
consisting of at least one male molding portion and two female
molding portions provided in a repetitive sequence of
male/female/female in the direction of rotation for each rotational
run over an angle of (360/3 n) degrees, and an intermediate element
molding portion provided between specified half body molding
portions in the direction of rotational movement for each (360/3 n)
degrees.
[0018] For every two rotational runs of the molding dies, a first
injection is carried out such that first and second half bodies are
molded by a combination of male and female molding portions, and an
intermediate element to be set between the first and second half
bodies is molded by a combination of intermediate element molding
portions. After the intermediate element is mated to and fitted in
the first half body molded at the first injection step, the first
half body in which the intermediate element is set is mated to and
abutted with a corresponding second half body so that the half
bodies are assembled into a molded product, and a second injection
is carried out such that melted resin is injected onto the abutting
portions of the two half bodies whereby the half bodies are joined
together. Thus, in every two rotational runs of the molding dies, a
hollow member with the intermediate element set between the first
and second half bodies can be obtained.
[0019] In the second aspect of the present invention, the apparatus
for manufacturing a synthetic resin hollow member comprises a pair
of molding dies for rotary injection molding (so-called DRI method)
assembled together so as to be opened and closed relative to each
other and rotatable over an angle of (360/3 n) degrees for each
turn relative to each other; the molding dies each having a half
body molding section consisting of at least one male molding
portion and two female molding portions provided in a repetitive
sequence of male/female/female in the direction of rotation for
each rotational run over an angle of (360/3 n) degrees, and an
intermediate element molding portion provided between specified
half body molding portions in the direction of rotational movement
for each (360/3 n) degrees; and wherein for every two rotational
runs of the molding dies, a first injection is carried out to mold
a first and a second half bodies and an intermediate element to be
set between the first and second half bodies, and after the
intermediate element is mated to and fitted in the first half body
molded at the first injection step, the first half body in which
the intermediate element is set is mated to and abutted with a
corresponding second half body so that the half bodies are
assembled into a molded product, and a second injection is carried
out such that melted resin is injected onto the abutting portions
of the two half bodies for joining the half bodies together,
whereby for every two rotational runs of the molding dies, a hollow
member with the intermediate element set between the first and
second half bodies can be obtained. Therefore, by employing the DRI
method it is possible to carry out the molding and butt-joining of
half bodies, and also the molding of an intermediate element in a
series of steps. Also it is possible to eliminate such manual work
as has been involved in setting the intermediate element in
place.
[0020] That is, as compared with the prior art wherein adhesive
bonding or heat melting is carried out for joining separate half
bodies, high bond strength of joined half bodies and good sealing
characteristics of the butt-joined surface can be more stably
secured; and by using the DRI method it is possible to achieve
higher production efficiency.
[0021] According to a third aspect of the present invention, there
is provided a synthetic resin hollow member adapted to incorporate
an intermediate element therein by placing the intermediate element
between a pair of synthetic resin-made half bodies, then causing
the two half bodies to abut against each other and joining them at
their abutting portions, wherein the synthetic resin hollow member
is manufactured by using a pair of rotary injection molding dies
which can be opened. and closed relative to each other and are
rotatable relative to each other at angular intervals of (360/6 n)
degrees, each die having a half body molding section consisting of
at least one male molding portion and two female molding portions
in a repetitive sequence of male/female/female in the direction of
rotation for each rotational run over an angle of (360/3 n)
degrees, each die also having an intermediate element molding
portion provided between specified half body molding portions in
the direction of rotation for each rotational run over an angle of
(360/3 n) degrees.
[0022] For every two rotational runs of the molding dies, a first
injection is carried out such that first and second half bodies are
molded by a combination of male and female molding portions, and an
intermediate element to be set between the first and second half
bodies is molded by a combination of intermediate element molding
portions. After the intermediate element is mated to and fitted in
the first half body molded at the first injection step, the first
half body in which the intermediate element is set is mated to and
abutted with a corresponding second half body so that the half
bodies are assembled into a molded product, and a second injection
is carried out such that melted resin is injected onto the abutting
portions of the two half bodies whereby the half bodies are joined
together. Thus, for every two rotational runs of the molding dies,
a finished product with the intermediate element set between the
first and second half bodies can be obtained.
[0023] In the third aspect of the present invention, the synthetic
resin hollow member is manufactured by using a pair of molding dies
for rotary injection molding (so-called DRI method) which can be
opened and closed relative to each other and are rotatable relative
to each other over an angle of (360/6 n) degrees for each turn,
each die having a half body molding section consisting of at least
one male molding portion and two female molding portions in a
repetitive sequence of male/female/female in the direction of
rotation for each rotational run over an angle of (360/3 n)
degrees, each die also having an intermediate element molding
portion provided between specified half body molding portions in
the direction of rotation for each rotational run over an angle of
(360/3 n) degrees; for every two rotational runs of the molding
dies, a first injection is carried out to mold a first and a second
half bodies, and an intermediate element to be set between the
first and second half bodies; after the intermediate element is
mated to and fitted in the first half body molded at the first
injection step, the first half body in which the intermediate
element is set is mated to and abutted with a corresponding second
half body so that the half bodies are assembled into a molded
product, and a second injection is carried out such that melted
resin is injected onto the abutting portions of the two half bodies
whereby the half bodies are joined together so that in every two
rotational runs of the molding dies, a finished product with the
intermediate element set between the first and second half bodies
can be obtained. Therefore, by employing the DRI method it is
possible to carry out the molding and butt-joining of half bodies,
and also the molding of an intermediate element in a series of
steps. Also it is possible to eliminate such manual work as has
been involved in setting the intermediate element in place.
[0024] That is, as compared with the prior art wherein adhesive
bonding or heat melting is carried out for joining separate half
bodies, high bond strength of joined half bodies and good sealing
characteristics of the butt-joined surface can be more stably
secured; and by using the DRI method it is possible to achieve
higher production efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is an explanatory view in longitudinal section taken
along lines A-C in FIG. 7 for illustrating a molding die assembly
in clamped condition with respect to an embodiment of the present
invention;
[0026] FIG. 2 is an explanatory view in front elevation of a rotor
in a stationary die of the molding die assembly;
[0027] FIG. 3 is an explanatory view in front elevation of a die
plate of a movable die of the molding die assembly;
[0028] FIG. 4 is an explanatory view in front elevation showing
matching of molding portions and dummy holes, and resin passage
connections in the rotor of the stationary die and the die plate of
the movable die at their initial positions;
[0029] FIG. 5 is an explanatory view in front elevation showing
matching of molding portions and dummy holes, and resin passages in
switched-over condition in the rotor and the die plate at
60.degree. turn position;
[0030] FIG. 6 is an explanatory view in front elevation showing
matching of molding portions and dummy holes, and resin passages in
switched-over condition at 120.degree. turn position of the rotor
and the die plate;
[0031] FIG. 7 is a perspective view schematically showing matching
of molding portions and dummy holes at initial positions of the
rotor of the stationary die and of the die plate of the movable
die;
[0032] FIG. 8 is a perspective view schematically showing matching
of molding portions and dummy holes at a 60.degree. forward turn
position of the rotor and die plate;
[0033] FIG. 9 is a perspective view schematically showing matching
of molding portions and dummy holes at a 120.degree. forward turn
position of the rotor and die plate;
[0034] FIG. 10 is a perspective view schematically showing matching
of molding portions and dummy holes at a 60.degree. reverse turn
position of the rotor and die plate;
[0035] FIG. 11 is a perspective view schematically showing matching
of molding portions and dummy holes at a 120.degree. reverse turn
position (initial position) of the rotor and die plate;
[0036] FIG. 12 is an explanatory view in section taken along the
line J1-O-J3 in FIG. 7 which shows matched portions of the rotor
and die plate;
[0037] FIG. 13 is an explanatory view in section taken along the
line O-J5 in FIG. 7 which shows matched portions of the rotor and
die plate;
[0038] FIG. 14 is an explanatory view in section taken along the
line J6-O-J2 in FIG. 7 which shows matched portions of the rotor
and die plate;
[0039] FIG. 15 is an explanatory view in section taken along the
line O-J4 in FIG. 7 which shows matched portions of the rotor and
die plate;
[0040] FIG. 16 is an explanatory view in section taken along the
line K1-O-K3 in FIG. 8 which shows matched portions of the rotor
and die plate;
[0041] FIG. 17 is an explanatory view in section taken along the
line O-K5 in FIG. 8 which shows matched portions of the rotor and
die plate;
[0042] FIG. 18 is an explanatory view in section taken along the
line K6-O-K2 in FIG. 8 which shows matched portions of the rotor
and die plate;
[0043] FIG. 19 is an explanatory view in section taken along the
line O-K4 in FIG. 8 which shows matched portions of the rotor and
die plate;
[0044] FIG. 20 is an explanatory view in section taken along the
line L1-O-L3 in FIG. 9 which shows matched portions of the rotor
and die plate;
[0045] FIG. 21 is an explanatory view in section taken along the
line O-L5 in FIG. 9 which shows matched portions of the rotor and
die plate;
[0046] FIG. 22 is an explanatory view in section taken along the
line L6-O-L2 in FIG. 9 which shows matched portions of the rotor
and die plate;
[0047] FIG. 23 is an explanatory view in section taken along the
line O-L4 in FIG. 9 which shows matched portions of the rotor and
die plate;
[0048] FIG. 24 is an explanatory view in section taken along the
line M1-O-M3 in FIG. 10 which shows matched portions of the rotor
and die plate;
[0049] FIG. 25 is an explanatory view in section taken along the
line O-M5 in FIG. 10 which shows matched portions of the rotor and
die plate;
[0050] FIG. 26 is an explanatory view in section taken along the
line M6-O-M2 in FIG. 10 which shows matched portions of the rotor
and die plate;
[0051] FIG. 27 is an explanatory view in section taken along the
line O-M4 in FIG. 10 which shows matched portions of the rotor and
die plate;
[0052] FIG. 28 is a perspective view of an oil strainer embodying
the present invention;
[0053] FIG. 29 is an explanatory view in top plan showing the oil
strainer;
[0054] FIG. 30 is an explanatory view in side elevation showing the
oil strainer; and
[0055] FIG. 31 is an explanatory view of the oil strainer in
longitudinal section taken along the Y-Y line in FIG. 29.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0056] One embodiment of the present invention will now be
described in detail with reference to the accompanying drawings
which illustrate by way of example the embodiment as applied to the
manufacturing of a synthetic resin-made oil strainer.
[0057] FIGS. 28 through 31 show an oil strainer W as a synthetic
resin hollow member embodying the invention. The oil strainer W is
a hollow member comprising an upper half body W.sub.U having an
outlet tube portion Wo, and a lower half body W.sub.L having an
inlet tube portion Wi, and has a filter,Wf (see FIG. 31) disposed
in a hollow interior thereof for filtering foreign matter present
in incoming oil.
[0058] The oil strainer W, as will be described in detail
hereinafter, is a product manufactured in the form of a hollow
member incorporating an intermediate element (filter Wf) by the
so-called die rotary injection (DRI) method such that upper and
lower half bodies W.sub.U, W.sub.L, and a filter Wf as the
intermediate element to be disposed in the hollow member are each
molded by one molding die, the half bodies W.sub.U and W.sub.L
being butt-joined in the molding die after the filter Wf having
been disposed in a space defined by the half bodies W.sub.U,
W.sub.L within the molding die.
[0059] As best shown in FIG. 31, there are provided channel-like
interior passages Wp of closed section which are formed preferably
along the outer peripheries of respective abutting surfaces of the
half bodies W.sub.U, W.sub.L, more preferably defined by wall
portions of respective half bodies W.sub.U and W.sub.L, such that
after the upper and lower half bodies W.sub.U and W.sub.L are
brought into abutment with each other, a resin mass (secondary
resin) for joining the half bodies together is filled into the
interior passage Wp.
[0060] In the present embodiment, the interior passage Wp is
configured to have a closed sectional configuration defined by wall
portions of the half bodies W.sub.U, W.sub.L. As an alternative,
however, it is possible to arrange that while the interior passage
is partially open at the time when the half bodies are in abutment
with each other, by setting the half bodies in a specified die, the
opening is closed by die surfaces so that a closed sectional
configuration is formed.
[0061] Next, the construction of molding dies for so-called die
rotary injection (DRI) employed in manufacturing (molding) the
above mentioned oil strainer W will be described.
[0062] FIG. 1 is an explanatory view showing a pair of molding dies
(stationary die 1 and movable die 2) as assembled together in
molding the oil strainer. As may be understood from the drawing,
the molding die assembly comprises a stationary die 1 connected to
a molding machine (e.g., injection molding machine, not shown), and
a movable die 2 which performs opening and closing operations
relative to the stationary die 1. As will be described in detail
hereinafter, the stationary die 1 is provided with a pivotal
mechanism for pivotally moving predetermined portions including the
molding portion of the die.
[0063] In FIG. 1, the stationary die 1 and the movable die 2 are
shown as being horizontally (right and left) mounted. In actual
setting, however, the arrangement of the dies 1, 2 is not limited
to such horizontal (right and left) arrangement, but the dies may,
for example, be disposed vertically arranged in opposed relation
for use.
[0064] The stationary die 1 includes a base plate 11 fixed to a
body portion 10, a sprue bush 12 fixed centrally to the base plate
11 and body portion 10, and a rotor 13 disposed coaxially with the
sprue bush 12. An injection head (not shown) of the molding machine
is fixed to the sprue bush 12.
[0065] The rotor 13 is basically configured to have a disc shape
and, centrally on its surface, a sprue 12a is open which is fitted
in a center portion of the sprue bush 12. Molding portions to be
described hereinafter are provided on the surface of the rotor
13.
[0066] The outer periphery of the rotor 13 is formed with a toothed
portion 13g which goes in mesh engagement with a drive gear 14
disposed at an adjacent location thereof. The drive gear 14 is
connected to a drive power source 15, for example, a hydraulic
motor, such that as the drive gear 14 is rotated by the drive power
source 15, according to the direction of the rotation and the
number of turns, the rotor 13 rotates for a predetermined angle
(360(/6 n) degrees each time in a predetermined direction.
[0067] That is, the toothed portion 13g of the rotor 13, the drive
gear 14, and the drive power source 15 constitute rotary mechanism
for rotating the rotor 13 a predetermined angle (360(/6 n) degrees
which correspond to "rotary mechanism" set forth in one of the
claims of the present invention.
[0068] In the present embodiment, n is preferably set at 1 (n=1) so
that the rotor 13 is rotated for 60 degrees each time.
[0069] Whilst, the movable die 2 includes a body portion 30, a base
plate 31 disposed in parallel to the body portion 30, and a die
plate 33 fixed to the body portion 30. The die plate 33 includes a
molding section to be described hereinafter.
[0070] The body portion 30 and base plate 31 are connected, for
example, to a hydraulic drive means (not shown) so that opening and
closing operation can be performed relative to the stationary die 1
at predetermined time intervals. Not specifically shown, though, on
the movable plate 2 side, there is provided an ejector mechanism
for ejecting a finished product W when the die assembly is opened
for taking out the finished product W.
[0071] FIG. 2 is an explanatory view in front elevation showing a
die matching surface of the rotor 13 of the stationary die 1. As
shown, on the die matching surface of the rotor 13 there are
provided five molding portions 20A-20E and one dummy hole 20 F
which are arranged about the center of the die matching surface of
the rotor 13 in circumferentially equally spaced relation (that is,
at such angular positions as are sequentially spaced apart by 60
degrees each). The five molding portions 20A-20E and one dummy hole
20F are all circular in shape when viewed in front elevation, and
their centers are positioned on a circumference (a pitch circle) of
a predetermined radius.
[0072] Of the five molding portions 20A-20E, three molding portions
20A, 20C and 20E are intended for molding half bodies W.sub.U,
W.sub.L and are at an angular position spaced 120 degrees (360/3 n
degrees) apart sequentially from each other. The molding portions
20A and 20E are both concavely shaped to serve as female molding
portions for use in molding one half body (for example, upper half
body W.sub.U). The molding portion 20C is a convexly shaped to
serve as a male molding portion for use in molding the other half
body (lower half body W.sub.L).
[0073] In other words, on the die matching surface of the rotor 13
there is provided a half body molding section consisting of one
male molding portion 20C and two female molding portions 20A, 20E
in a repetitive sequence of male/female/female at angular intervals
of 120 degrees (360/3 n degrees) in the direction of rotation.
[0074] The molding portion 20B provided between the half body
molding portion 20A and the half body molding portion 20C, and the
molding portion 20D provided between the half body molding portion
20C and the half body molding portion 20E are both intended for
molding a filter Wf as an intermediate element. These molding
portions are also at an angular position spaced apart 120 degrees
(360/3 n degrees) sequentially from each other.
[0075] In other words, on the die matching surface of the rotor 13
there are provided intermediate element molding portions 20B, 20D
between half body molding portions 20A and 20C and between 20C and
20E respectively at angular intervals of 120 degrees (360/3 n
degrees) in the direction of rotation.
[0076] Between the half body molding portion 20E and the half body
molding portion 20A there is provided a dummy hole 20F which is
diametrically larger by a predetermined quantity than individual
half body molding portions 20A, 20C, and 20E.
[0077] The dummy hole 20F, as will be described hereinafter, is
such that during one cycle of molding operation the dummy hole is
put in combination with a molding portion provided on the opposite
side (die plate 33 of the movable die 2) so as to function as a
means for adjustment of operation in the direction of rotation.
[0078] The die matching surface of rotor 13 of the stationary die 1
is not provided with any resin passage connected to individual
molding portions 20A-20E, but as will be described hereinafter,
there are provided a group of (five in all) elongated channel-like
changeover slots 22A-22E for switching over connections between
resin passages associated with molding portions of the movable die
2 and a sprue opening 21 of the sprue bush 12.
[0079] The changeover slots 22A-22E are respectively so formed as
to be generally oriented toward corresponding molding portions
20A-20E.
[0080] On the outer periphery of the rotor 13, as earlier stated, a
toothed portion 13g which is in mesh engagement with the drive gear
14 is provided over an arcuate length corresponding to an angle of
at least 120 degrees so that as the drive gear 14 rotates (that is,
according to the direction of rotation and number of turns made)
the rotor 13 rotates at least two times for 60 degrees each time in
a predetermined direction. The control of rotational movement of
the drive gear 14 (that is, control of rotation of the rotor 13) is
carried out by controlling the drive source 15, such as hydraulic
motor.
[0081] In the present embodiment, the rotor 13 is of such
arrangement that it is rotated forward twice in succession at
predetermined times for an angle of 60 degrees each and is then
rotated reverse twice in succession for an angle of 60 degrees
each.
[0082] Whilst, FIG. 3 is an explanatory view in front elevation
showing a die matching surface of the die plate 33 of the movable
die 2. As shown, on the die matching surface of the die plate 33
there are provided five molding portions 40A-40E and one dummy hole
40F which are arranged about the center of the die matching surface
of the die plate 33 in circumferentially equally spaced relation
(that is, at such angular positions as are sequentially spaced
apart by 60 degrees each). The five molding portions 40A-40E and
one dummy hole 40F are all circular in shape when viewed in front
elevation, and their centers are positioned on a circumference (a
pitch circle) of a predetermined radius.
[0083] Of the five molding portions 40A-40E, three molding portions
40A, 40C and 40E are intended for molding half bodies W.sub.U,
W.sub.L and are at an angular position spaced 120 degrees (360/3 n
degrees) apart sequentially from each other. The molding portions
40A and 40E are both concavely shaped to serve as female molding
portions for use in molding one half body (for example, lower half
body W.sub.L). The molding portion 40C is a convexly shaped to
serve as a male molding portion for use in molding the other half
body (lower half body W.sub.U).
[0084] In other words, as is the case with the rotor 13 side, on
the die matching surface of the die plate 33 there is provided a
half body molding section consisting of one male molding portion
40C and two female molding portions 40A, 40E in a repetitive
sequence of male/female/female at angular intervals of 120 degrees
(360/3 n degrees) in the direction of rotation.
[0085] The molding portion 40B provided between the half body
molding portion 40A and the half body molding portion 40C, and the
molding portion 40D provided between the half body molding portion
40C and the half body molding portion 40E are both intended for
molding a filter Wf as an intermediate element. These molding
portions are also at an angular position spaced apart 120 degrees
(360/3 n degrees) sequentially from each other.
[0086] In other words, on the die matching surface of the die plate
33 of the movable die 2, same as the rotor 13 side, there are
provided intermediate element molding portions 40B, 40D between
half body molding portions 40A and 40C and between 40C and 40E at
angular intervals of 120 degrees (360/3 n degrees) in the direction
of rotation.
[0087] Between the half body molding portion 40E and the half body
molding portion 40A there is provided a dummy hole 40F which is
diametrically larger by a predetermined quantity than individual
half body molding portions 40A, 40C, and 40E.
[0088] As will be described hereinafter, the dummy hole 40F, which
is similar to the dummy hole 20F provided on the rotor 13 side, is
such that during one cycle of molding operation it is put in
combination with a molding portion provided on the opposite side
(die plate 33 of the movable die 2) so as to function as a means
for adjustment of operation in the direction of rotation.
[0089] The die plate 33 of the movable die 2 is formed with two
kinds of resin passages, including a centrally formed tributarily
branched resin passage 41, and resin passages 42A-42E connected
directly to the molding portions 40A-40E.
[0090] Resin passages 42A and 42E, two each, are respectively
connected to the female molding portions 40A and 40E, and resin
passages 42B, 42C, and 42D, one each, are respectively connected to
other molding portions 40B, 40C and 40D. As will be described
hereinafter, the resin passages 42A and 42E, two each, connected to
the female molding portions 40A and 40E are used in such a way that
one of the each two passages (at left side as viewed from the
center of the die plate 33) is used for the purpose of molding half
bodies W.sub.U, W.sub.L and the other (at right side as viewed from
the center of the die plate 33) is used when introducing melted
resin into an interior passage Wp of the butt-engaged upper and
lower half bodies W.sub.U, W.sub.L for joining the half bodies
together.
[0091] When the movable die 2 is closed relative to the stationary
die 1, the branched resin passage 41 is branched with its center
portion as a proximal point which corresponds to the opening 21 of
the sprue 12a of the sprue bush 12. Five branches are provided in
corresponding relation to resin passages 42A-42E connected
respectively to the molding portions 40A-40E. These branches are
positioned so that the distal end of each branch is spaced a
certain distance on its extension from one end of a corresponding
resin passage.
[0092] When the movable die 2 is closed relative to the stationary
die 1, specified resin passages 42A-42E are connected to the
branched resin passage 41 (that is, sprue opening 21) by changeover
slots 22A-22E provided on the rotor 13 of the stationary die 1.
This connection is changed over by the rotation of the rotor
13.
[0093] The process of molding an oil strainer W to be carried out
by using molding dies constructed as described above will be
described herein below.
[0094] Initially, the stationary die 1 (rotor 13) is put in
combination with the movable die 2 (die plate 33) in such a
condition as illustrated in FIG. 7. In this case, combinations of
molding portions of the two dies 1, 2, and dummy holes of the two
dies 1, 2 are as follows:
[0095] Movable die 2, half body molding portion 40A
(female)/stationary die 1, half body molding portion 20C (male)
[0096] Movable die 2, intermediate element molding portion
40B/stationary die 1, intermediate element molding portion 20B
[0097] Movable die 2, half body molding portion 40C
(male)/stationary die 1, half body molding portion 20A (female)
[0098] Movable die 2, intermediate element molding portion
40D/stationary die 1, dummy hole 20F
[0099] Movable die 2, half body molding portion 40E
(female)/stationary die 1, half body molding portion 20E
(female)
[0100] Movable die 2, dummy hole 40F/stationary die 1, intermediate
element molding portion 20D
[0101] In this case, changeover slots 22A-22E of rotor 13 of
stationary die 1 are respectively at such turn positions as shown
by double-dash chain lines in FIG. 4.
[0102] That is, changeover slot 22A causes resin passage 42C for
half body molding portion 40C of movable die 2 to communicate with
branched resin passage 41; changeover slot 22B causes resin passage
42B for intermediate element molding portion 40B of movable die 2
to communicate with branched resin passage 41; changeover slot 22C
causes one (half body molding resin passage) of resin passages 42A
for molding portion 40A of movable die 2 to communicate with
branched resin passage 41; changeover slot 22E causes the other
(resin passage for filling melted resin into the interior passage
Wp of molded product W) of the resin passages 42E for half body
molding portion 40E of movable die 2 with branched resin passage
41.
[0103] In this case, changeover slot 22D is oriented toward the
dummy hole 40F which has no resin passage, and no changeover slot
is connected to resin passage 42D for the intermediate element
molding portion 40D of movable die 2 which is mated to the dummy
hole 20F of stationary die 1. That is, for any combination with
which dummy hole 20F or 40F is associated, no communication with
branched resin passage 41 could be obtained.
[0104] Therefore, in this condition, the movable die 2 is brought
into abutment against the stationary die 1, and die clamping (first
die clamping) is carried out, whereby molding portions of
stationary die 1 and movable die 2 are correspondingly mated to
define the following cavities.
[0105] That is, in a portion extending along the line J1-O-J3 in
FIG. 7, as FIG. 12 shows, half body molding portion 40A (female) of
movable die 2 (die plate 33) is mated with half body molding
portion 20C (male) of stationary die 1 (rotor 13) to define a
molding cavity corresponding to the lower half body W.sub.L, and
half body molding portion 40C (male) of movable die 2 (die plate
33) is mated to half body molding portion 20A (female) of
stationary die 1 (rotor 13) to define a molding cavity
corresponding to the upper half body W.sub.U.
[0106] In a portion extending along the line O-J5 in FIG. 7, as
FIG. 13 shows, half body molding portion 40E (female) of movable
die 2 (die plate 33) is mated with half body molding portion 20E
(female) of stationary die 1 (rotor 13), and the lower, half body
W.sub.L and filter Wf held in half body molding portion 40E at the
die plate 33 side are mated to the upper half body W.sub.U held in
the half body molding portion 20E at the rotor 13 side.
[0107] A finished product W can be obtained by injection filling a
melted resin mass into interior passage Wp with respect to the so
matched combination. It is to be noted in this conjunction that the
half bodies W.sub.U, W.sub.L and filter Wf are all products molded
in the previous cycle.
[0108] Further, in a portion extending along the line J6-O-J2 in
FIG. 7, as FIG. 14 shows, intermediate element molding portion 40B
of movable die 2 (die plate 33) is mated with intermediate element
molding portion 20B of stationary die 1 (rotor 13) to define a
molding cavity corresponding to the intermediate element (filter
Wf). It is noted that the combination of the intermediate element
molding portion 40D at the die plate 33 side and the dummy hole 20F
at the rotor 13 side does not constitute a molding cavity., because
the related resin passage is not connected to the sprue opening
21.
[0109] In a portion extending along the line O-J4 in FIG. 7, as
FIG. 15 shows, dummy hole 40F at the die plate 33 side is mated to
intermediate element molding portion 20D at the rotor 13 side, but
for the same reason no molding cavity could be formed.
[0110] When melted resin is injected (first injection) from a
molding machine (not shown) in the above described clamped die
condition (first die clamping), the melted resin is supplied
through the opening 21 of the sprue 12a into the resin passages
42A, 42B, 42C, 42E which are in communication with the branched
resin passage 41. It is noted that for the material resin in the
present embodiment a nylon resin mixed with a glass-reinforced
fiber material, for example, was used.
[0111] As a result, in molding cavities formed by combinations of
molding portions of the stationary die 1 and movable die 2 the
following molded products are produced.
[0112] Half body molding portion 40A (female)/half body molding
portion 20C (male): lower half body W.sub.L
[0113] Intermediate element molding portion 40B/intermediate
element molding portion 20B: filter Wf
[0114] Half body molding portion 40C (male)/half body molding
portion 20A (female): upper half body W.sub.U
[0115] Half body molding portion 40E (female)/half body molding
portion 20E (female): finished product W
[0116] It is to be noted in this connection that in the case of
first resin injection being made during rise time, molded half
bodies (upper half body W.sub.U and lower half body W.sub.L) and
filter Wf are not present in the molding cavity defined by the half
body molding portion 40E (female)/half body molding portion 20E
(female); therefore, melted resin injection is carried out after a
dummy having same outer shape as one formed by abutting upper half
body W.sub.U and lower half body W.sub.L with each other is set in
the cavity.
[0117] Next, the movable die 2 is retreated from the stationary die
1 for die opening. A finished product W obtained through the
combination of half body molding portion 40E (female) at the die
plate 33 side and the half body molding portion 20E (female) at the
rotor 13 side is taken out. Thereafter, as FIG. 8 shows, rotor 13
is rotated forward for 60 degrees (first die rotation). As a result
of this first die rotation, the following combinations are made
with respect to molding portions and dummy holes of stationary die
1 and movable die 2.
[0118] Movable die 2, half body molding portion 40A
(female)/stationary die 1, intermediate element molding portion
20B
[0119] Movable die 2, intermediate element molding portion
40B/stationary die 1, half body molding portion 20A (female)
[0120] Movable die 2, half body molding portion 40C
(male)/stationary die 1, dummy hole 20F
[0121] Movable die 2, intermediate element molding portion
40D/stationary die 1, half body molding portion 20E (female)
[0122] Movable die 2, half body molding portion 40E
(female)/stationary die 1, intermediate element molding portion
20D
[0123] Movable die 2, dummy hole 40F/stationary die 2,half body
molding portion 20C (male)
[0124] In this case, changeover slots 22A-22E of the rotor 13 of
the stationary die 1 are respectively at such turn positions as
shown by double dash chain lines in FIG. 5, and none of the
changeover slots 22A-22E are connected to resin passages 42A-42E of
the die plate 33 of the movable die 2. The resin passages 42A-42E
are not in communication with the branched resin passage 41.
[0125] In this condition, the movable die 2 is brought into
abutment against the stationary die 1, and die clamping is carried
out, whereby molding portions of stationary die 1 and movable die 2
are brought-into engagement as follows.
[0126] That is, in a portion extending along the line K1-O-K3 in
FIG. 8, as FIG. 16 shows, half body molding portion 40A (female) of
movable die 2 (die plate 33) is mated with intermediate element
molding portion 20B of stationary die 1 (rotor 13) so that a filter
Wf molded at the first injection step and held in intermediate
element molding portion 20B is brought into engagement with a lower
half body W.sub.L molded at the first injection step and held in
the half body molding portion 40A.
[0127] Half body molding portion 40C (male) of the movable die 2 is
mated with dummy hole 20F of the stationary die 1 (rotor 13). In
this combination, no product (part) molded by first injection is
held on either side.
[0128] At a portion extending along line O-K5 in FIG. 8, as FIG. 17
shows, half body molding portion 40E (female) of the movable die 2
(die plate 33) is mated with intermediate element molding portion
20D of the stationary die 1 (rotor 13), but no part molded by first
injection is held on either side.
[0129] At a portion extending along line K6-O-K2 in FIG. 8, as FIG.
18 shows, the intermediate element molding portion 40B of the
movable die 2 (die plate 33) is mated with half body molding
portion 20A of the stationary die 1 (rotor 13). An upper half body
W.sub.U molded at the first injection step is held in the half body
molding portion 20A. Intermediate element molding portion 40D of
the movable die 2 (die plate 33) is mated with half body molding
portion 20E of the stationary die 1 (rotor 13), but no product
molded by first injection is held on either side.
[0130] At a portion extending along line O-K4 in FIG. 8, as FIG. 19
shows, dummy hole 40F on the die plate 33 side is mated with half
body molding portion 20C on the rotor 13 side, but no product
molded by first injection is held on either side.
[0131] Thereafter, movable die 2 is retreated again relative to
stationary die 1 for die opening and, as FIG. 9 shows, the rotor 13
is rotated further 60 degrees forward (i.e., 120 degrees from
initial position: second rotation). As a result of this second
rotation, combinations of molding portions and dummy holes of
stationary die I and movable die 2 are as follows.
[0132] Movable die 2, half body molding portion 40A
(female)/stationary die 1, half body molding portion 20A
(female)
[0133] Movable die 2, intermediate element molding portion
40B/stationary die 1, dummy hole 20F
[0134] Movable die 2, half body molding portion 40C
(male)/stationary die 1, half body molding portion 20E (female)
[0135] Movable die 2, intermediate element molding portion
40D/stationary die 1, intermediate element molding portion 20D
[0136] Movable die 2, half body molding portion 40E
(female)/stationary die 1, half body molding portion 20C (male)
[0137] Movable die 2, dummy hole 40F/stationary die 1, intermediate
element molding portion 20B
[0138] In this case, changeover slots 22A-22E of rotor 13 of
stationary die 1 are respectively at such turn positions as shown
by double-ash chain lines in FIG. 6.
[0139] That is, changeover slot 22A causes the other of the resin
passages 42A (resin passage for melted resin filling into interior
passage Wp for molded product W) for half body molding portion 40A
of movable die 2 to communicate with branched resin passage 41;
changeover slot 22C causes one of the resin passages 42E (resin
passage for half body molding) for half body molding portion 40E of
movable die 2 to communicate with branched resin passage 41;
changeover slot 22D causes intermediate element molding resin
passage 42D for intermediate element molding portion 40D of movable
die 2 to communicate with branched resin passage 41; and changeover
slot 22E causes resin passage 42C for half body molding portion 40C
of movable die 2 to communicate with branched resin passage 41.
[0140] In this case, changeover slot 22B is oriented toward the
dummy hole 40F which has no resin passage, and no changeover slot
is connected to resin passage 42B for the intermediate element
molding portion 40B of movable die 2 which is mated with the dummy
hole 20F of stationary die 1. That is, for any combination with
which dummy hole 20F or 40F is associated, no communication with
branched resin passage 41 could be obtained.
[0141] Therefore, in this condition, the movable die 2 is brought
into abutment against the stationary die 1, and die clamping (first
die clamping) is carried out, whereby molding portions of
stationary die 1 and movable die 2 are correspondingly mated to
define the following cavities.
[0142] That is, in a portion extending along the line L1-O-L3 in
FIG. 9, as FIG. 20 shows, half body molding portion 40A (female) of
movable die 2 (die plate 33) is mated with half body molding
portion 20A (female) of stationary die 1 (rotor 13), and lower half
body W.sub.L and filter Wf held in half body molding portion 40A
(male) of die plate 33 is mated to upper half body W.sub.U held in
half body molding 20 portion 20A of rotor 13. A melted resin mass
is supplied by injection into the interior passage Wp toward the
mated portions to obtain a finished product W.
[0143] Half body molding portion 40C (male) of the movable die 2
(die plate 33) is mated with half body molding portion 20E (female)
of the stationary die 1 (rotor 13), whereby a molding cavity
corresponding to upper half body W.sub.U is obtained.
[0144] In a portion extending along line O-L5 in FIG. 9, as FIG. 21
shows, half body molding portion 40E (female) of the movable die 2
(die plate 33) is mated with half body molding portion 20C (male)
of the stationary die 1 (rotor 13), whereby a molding cavity
corresponding to lower half body W.sub.L is obtained.
[0145] In a portion extending along line L6-O-L2 in FIG. 9, as FIG.
22 shows, intermediate element molding portion 40D of the movable
die 2 (die plate 33) is mated with intermediate element molding
portion 20D of the stationary die 1 (rotor 13) to define a molding
cavity corresponding to an intermediate element (filter Wf). The
combination of the intermediate element molding portion 40B of the
die plate 33 side and the dummy hole 20F on the rotor 13 side is
not in communication with the sprue opening 21. Therefore, this
combination does not form any molding cavity.
[0146] In a portion extending along line O-L4 in FIG. 9, as FIG. 23
shows, dummy hole 40F on the die plate 33 side is mated with
intermediate element molding portion 20B of the rotor 13. However,
this combination does not form any molding cavity either.
[0147] In the above described die clamped condition (second die
clamping), when melted resin is injected (second injection) from a
molding machine (not shown), the melted resin is supplied through
the opening 21 of the sprue 12a into resin passages 42A, 42C, 42D,
42E which are in communication with the branched resin passage
41.
[0148] As a result, in molding cavities defined by combinations of
respective molding portions of the stationary die 1 and movable die
2, molded products are obtained as follows.
[0149] Half body molding portion 40A (female)/half half body
molding portion 20A (female): finished product W
[0150] Intermediate element molding portion 40D/intermediate
element molding portion 20D: filter Wf
[0151] Half body molding portion 40C (male)/half body molding
portion 20E (female): upper half body W.sub.U
[0152] Half body molding portion 40E (female)/half body molding
portion 20C (male): lower half body W.sub.L
[0153] Then, die opening is made by retreating the movable die 2
relative to the stationary die 1, and the finished product W
obtained by the combination of half body molding portion 40A
(female) on the die plate 33 side and half body molding portion 20A
(female) on the rotor 13 side is taken out. In this way, one
finished product W is obtained on the second turn from the initial
position.
[0154] Thereafter, as FIG. 10 shows, rotor 13 is reversed 60
degrees to return the rotor 13 to the first turn position (see FIG.
8). As a result of this reversal, combinations of respective
molding portions and dummy holes of stationary die 1 and movable
die 1 are same as those at the first turn position shown in FIG. 8,
that is, as shown below.
[0155] Movable die 2, half body molding portion 40A
(female)/stationary die 1, intermediate element molding portion
20B
[0156] Movable die 2, intermediate element molding portion
40B/stationary die 1, half body molding portion 20A (female)
[0157] Movable die 2, half body molding portion 40C
(male)/stationary die 1, dummy hole 20F
[0158] Movable die 2, intermediate element molding portion
40D/stationary die 1, half body molding portion 20E (female)
[0159] Movable die 2, half body molding portion 40E
(female)/stationary die 1, intermediate element molding portion
20D
[0160] Movable die 2, dummy hole 40F/stationary die 1, half body
molding portion 20C (male)
[0161] In this case, turn positions of changeover slots 22A-22E at
the rotor 13 of the stationary die 1 are same as those shown by
double dash chain lines in FIG. 5, and none of the slots 22A-22E
are connected to resin passages 42A-42E. Therefore, these slots
42A-to 42E are not in communication with the branched resin passage
41.
[0162] In this condition, the movable die 2 is brought into closure
with the stationary die 1, whereby molding portions of the
stationary die 1 are engaged with those of the movable die 2 in the
following combinations.
[0163] That is, in a portion extending along line M1-O-M3 in FIG.
10, as FIG. 24 shows, half body molding portion 40A (female) of
movable die 2 (die plate 33) is mated with intermediate element
molding portion 20B of stationary die 1 (rotor 13), and half body
molding portion 40C (male) of movable die 2 (die plate 33) is mated
with dummy hole 20F of stationary die 1 (rotor 13). Neither of
these combinations hold a molded product resulting from second
injection.
[0164] In a portion extending along line O-M5 in FIG. 10, as FIG.
25 shows, a filter Wf held in the intermediate element molding
portion 20D, i.e., a product molded at second injection step, is
fitted to a lower half body W.sub.L, a product molded at second
injection step and held in the half body molding portion 40E.
[0165] In a portion extending along line M6-O-M2 in FIG. 10, as
FIG. 26 shows, intermediate element molding portion 40D of movable
die 2 (die plate 33) is mated with half body molding portion 20E of
stationary die 1 (rotor 13). In the half body molding portion 20E
is held an upper half body W.sub.U molded at second injection step.
Intermediate element molding portion 40B of movable die 2 (die
plate 33) is mated with half body molding portion 20A of stationary
die 1 (rotor 13), but in this case no molded product from first
injection step is held on either side.
[0166] In a portion extending along line O-M4 in FIG. 10, as FIG.
27 shows, dummy hole 40F on the die plate 33 side is mated with
half body molding portion 20C on the rotor 13 side, but no molded
product from second injection step is held on either side.
[0167] Subsequently, die opening is carried out again by causing
the movable die 2 to retreat relative to stationary die 1, and as
FIG. 11 shows, the rotor 13 is again reversed 60 degrees
(120.degree. reversal from 2nd turn position). Thus, rotor 13
returns to its initial position (see FIG. 7).
[0168] Therefore, combinations of molding portions of stationary
dies 1 with molding portions of movable die 2, and of dummy holes
are same as the combinations at initial positions shown in FIG. 7.
In this case, rotational positions of changeover slots 22A-22E on
the rotor 13 of stationary die 1 are same as the initial positions
shown by double dash chain lines in FIG. 4.
[0169] Further, in this condition, the movable die 2 is brought
into closure with the stationary die 1 and die clamping (first die
clamping in the next cycle) is made, so that molding portions of
the stationary die 1 and those of the movable die 2 are mated into
combinations. Thus, molding cavities similar to those at initial
positions shown in FIG. 7 and FIGS. 12 to 15 can be obtained.
[0170] In this clamped die condition (first die clamping in the
next cycle), melted resin injection (first injection in the next
cycle) from a molder (not shown) is carried out, whereby in molding
cavities formed by combinations of molding portions of stationary
die 1 and movable die 2 the following molded products are produced
in the same way as in aforesaid first injection.
[0171] Half body molding portion 40A (female)/half body molding
portion 20C (male): lower half body W.sub.L
[0172] Intermediate element molding portion 40B/intermediate
element molding portion 20B: filter Wf
[0173] Half body molding portion 40C (male)/half body molding
portion 20A (female): upper half body W.sub.U
[0174] Half body molding portion 40E (female)/half body molding
portion 20E (female): finished product W
[0175] Then, die opening is carried out again by causing the
movable die 2 to retreat relative to stationary die 1, and a
finished product W obtained by the combination of half body molding
portion 40E (female) on the die plate 33 side and half body molding
portion 20E (female) on the rotor 13 side is taken out.
[0176] That is, one additional finished product W can be obtained
by carrying out two reversal runs from the 120.degree. turn
position.
[0177] Thus, by repetitively carrying out the steps illustrated in
FIGS. 7 to 11 (process of from initial position to return
to-initial position) it is possible to obtain one synthetic resin
hollow member (oil strainer W) with an intermediate element (filter
Wf) set between upper and lower half bodies W.sub.U, W.sub.L for
each two 60.degree. turns of the molding die (rotor 13).
[0178] As described above, according to the present embodiment, one
synthetic resin hollow member having a filter Wf set between upper
and lower half bodies W.sub.U, W.sub.L can be obtained for each two
60.degree. turns. This makes it possible to carry out the steps of
molding and butt-joining of half bodies W.sub.U, W.sub.L and
molding of filter Wf as a series of steps using the DRI method.
Further, since the job of setting filter Wf in upper or lower half
bodies W.sub.U, W.sub.L is automatically performed in the dies 1,
2, such troublesome manual operations as may otherwise be required
can be eliminated.
[0179] That is, as compared with the prior art in which adhesive
and/or thermal fusion is used for joining half bodies, present
invention provides for good improvement in production efficiency,
with high bond strength and good sealing performance secured with
respect to abutting portions of half bodies W.sub.U, W.sub.L
through utilization of the DRI method.
[0180] The foregoing embodiment relates to an oil strainer, but the
present invention is not limited to use in such an application. The
invention is effectively applicable to other kinds of synthetic
resin structures having an intermediate element set between a pair
of synthetic resin half bodies. In the present embodiment, n in
(360/6 n) degrees and (360/3 n) degrees is 1 (n=1), but this n may
be other integer or natural number. In this case, a larger number
of molding portions are provided in one die assembly, it being thus
possible to increase the number of finished products obtainable in
each cycle.
[0181] Therefore, the present invention is not limited to above
described embodiment. Obviously, various improvements,
modifications, and design changes are possible without departing
from the spirit and scope of the invention.
* * * * *